Fluid couplings are known in which a female half or socket, connected to a source of pressure fluid, receives a male half or plug on the extension tube which, therefore, must be specially provided with such a fitting. Other conventional couplings dispense with the need for a male fitting by utilizing a clamp designed to grip an extremity of a hose or pipe to be supplied with fluid from the associated source. Such clamps are relatively complex and correspondingly expensive; moreover, they do not always have a firm grip on the tube, especially in the case of a rubber hose or the like.